Conventional block redundancy circuits may disconnect defective bitlines from a power supply using either fuses or gated loads. Conventional block redundancy circuits (i) only address standby current related to bitline defects, (ii) do not address defects related to intercell problems and (iii) are costly from a die area point of view.
Referring to FIG. 1, a conventional circuit 10 used for block and/or column redundancy is shown. The circuit 10 comprises a fuse 12 and a fuse 14. The fuses 12 and 14 disconnect defective bitlines BIT and BITB from the power supply of the circuit 10.
Referring to FIG. 2, another conventional circuit 20 used for block redundancy is shown. The circuit 20 comprises a gate 22, a number of transistors 24a-24n and a number of memory cells 26a-26n. The transistors 24a-24n disconnect defective bitlines BIT and BITB from the power supply of the circuit 20. The transistors 24a-24n are controlled by the gate 22.
Referring to FIG. 3, another conventional circuit 30 for block redundancy is shown. The circuit 30 comprises a transistor 32, a number of transistors 34a-34n and a number of memory cells 36a-36n. The transistor 32 supplies power to the circuit 30. The transistors 34a-34n are coupled between the power supply and the bitlines BIT and BITB. The transistors 34a-34n control the power supplied to the bitlines BIT and BITB. Transistor 32 disconnects the power supply of circuit 30 from the defective bitlines BIT and BITB.